Question
In 0.1 s, the current in a coil increases from 1 A to 1.5A. If inductance of coil is 60 mH, then induced current in external resistance of 32 will be
1 A
0.5 A
0.2 A
0.1 A
Solution
D.
0.1 A
The magnitude of induced emf in a circuit is equal to the inductance × rate of current change and a circuit has an inductance of one Henry will have one volt induced in the circuit when the circuit changes at a rate of one ampere per second.
When a current in coil changes, it induces a back emf in the same coil. The self-induced emf is given by
Induced emf,
=
0.3 V
Induced current,
i =
=
i = 0.1 A
